Robert irving cowen



Patented Jan. 27, 1931 UNITED STATES PATENT OFFICE ROBERT IRVING COWEN, OF NEW YORK, N. Y.

COLORED AND TINTED PARCHMENT PAPER AND THE LIKE AND PROCESS FOR THE MANUFACTURE OF THE SAME No Drawing. Original application filed November 19, 1925, Serial No. 70,196. Divided and this application filed March 6, 1928. Serial No. 259,612.

Hitherto the manufacturers of parchment paper have not been able to produce satisfactory and reliable results in making tinted is made by passlng unsized paper through a parchmentizing bath, for instance sulphuric acid, and then through a clear Water bath in order thoroughly to wash the paper free from excess of the acid. By this treatment a surface film of amyloid is formed upon both sides of the paper and around each fiber, the thickness of such film depending principally upon the time of immersion of such unsized paper in the said bath, the temperature of the bath, concentration of the acid, the texture of the paper, etc. This amyloid film or coating produces so-called 'parchment paper or vegetable parchment. In the process heretofore emplo ed for the production of colored papers 0 this character, the tint or color is incorporated in the beaters, or applied to the web by a print roll before or after going through the calenders as stated; by this process the result is not always satisfactory, and the depth of shadeand the number of colors which can be speciall utilized are limited.

- I colored parchment paper is to be made by adding the dyestufi' to the heaters, the manufacturer is limited as to the dyestuffs he can use for the following reasons. Acid and direct dyes cannot be used without a mordant, as they will not attach themselves to the fibers with any permanency and will mostly be washed out in the white water 1 when the beaten stock is run on tothe wire.

If a mordant, such as rosin size and alum, or a combination of the two is used, the paper will not parchmentize properly or at all when it is run through the parchmentizing bath.

Thus the acid and direct dyes cannot be used satisfactorily for coloring the paper in the beaters. However basic dyes will attach themselves to the fibers without the use of a mordant, although some will naturally be lost in the white water. On the other hand, many basic dyes'will be destroyed or decolorized when the paper is put into the parchmentizing bath, or dissolved by it. On subsequent washing out of the acid the concentration of dye left in the paper would be too small to color it satisfactorily.

I have found that papers of this class can be produced so as to enable the manufacturer to employ a wider range of colors and to do this more economically and more satisfactorily by my process than has been possible to do with the existing methods, and it is also possible to produce, for instance, a black'parchment paper of highly satisfactory quality and which hitherto has not been made satisfactorily. For instance, I am able,

. paper its amyloid coating. I have found that there are several types of coal-tar dyes espe cially which will do the work very satisfactorily in the manner indicated.

On adding the organic dye 'to concentrated sulphuric acid, say of about seventy-five per cent strength, it may be, depending upon the character of the dye 1) left unchanged chemically; (2) it may be changed to some other color, and upon subsequent dilution, that color may disappear and the original color return; (3) it may be changed to a different color, and that color may remain on dilution; (4) the dye may be entirely decomposed and be useless for further operation;

or, again (5) the dye may not dissolve in the acid solution at all.

The organic acid dyes, or most of them at least, are soluble in sulphuric acid, and, although some of these change in color or shade through the action of the acid or may give a colorless or nearly colorless parchmentizing bath, the original color reappears upon pass ing the treated paper through the water bath for washing out the excess of acid, and the paper is found to have been colored in a very satisfactory manner.

This class of acid dyes is mainly soluble in water, but, after the treatment in the manner indicated, the dye, being incorporated in the amyloid film itself, washes out very little in the subsequent treatment of the water bath which is used to wash out the excess of acid. Obviously any dye which is chemically decompose entirely by the acid is not serviceable.

I have also found that dyes which are insoluble in the acid bath may be used if they are present in fine suspension. For instance, when I use national Erie fast scarlet (color index No. 326) in such a suspension in the acid bath, the paper presents the same color as the plain parchment, but, when the paper is subsequently washed in a diluting bath, the dye begins to dissolve and colors the paper quite satisfactorily.

As an illustration of some of my experiences with various organic dyes of different classes and the results to be obtained therewith, I ma state at this point that chinoline yellow (color index No. 801) produces'a yellow dye bath and produces a fine yellow color in the paper; auramine O concentrated (color index No. 655) gives a colorless acid bath, but the color develops again on washing and produces a good dyeing effect; orange A (color index No. 151) produces a red dye bath, but gives a good orange color to the paper after washing crocein scarlet C (color index No. 252) produces a purple acid bath, but gives a good scarlet color in the finished paper; national Erie fast scarlet (color index No. 326), which is insoluble in the acid solution and must therefore be suspended therein, produces a satisfactory color after passing through the wash bath; acid scarlet 3 R (color index No. 196) dissolves in the acid bath to a wine-red color and gives a good red shade in the finished paper; acid blue R (color index No. 672) dissolves in the acid bath with a brownish-green color that gives a ood blue color effect in the paper; acid blue F (color index No. 671) dissolves in the acid with a blue color and gives the same effect in the paper after treatment; acid violet 4 B N S (color index No. 695) dissolves in the acid bath with a yellow color and dyes the paper purple after passing through the wash bath; acid green double (color index 666) dissolves with a yellowish-brown color but gives a good green colorin efiect in the aper; and similarly napht ylamine black (color index No. 308) produces a blueblack solution and produces a good black finished paper.

On the other hand, I found some dyes, as, for example, pontamine yellow (color index No. 365) and polar red B concentrated (color index No. 430) are permanently destro ed by the acid and can therefore not be used for the purpose stated.

In general, therefore, it will be seen that the paper produced by this process affords awide range of color; that the dyes are incorporated in the amyloid film; that the shade of color can be readily controlled by the amount and character of the dye put into the acid bath, which cannot be so well and conveniently done when the coloring matter is introduced into the heaters. Obviously the amount of dye depends upon the nature of the dye itself and the depth of color which itis desired to obtain, and will vary considerably, ranging from, say, a fraction of an ounce to several ounces per pound of acid.

To illustrate in further detail my manner of producing this improved colored parchment paper or vegetable parchment, I give the following example of the manner in which the processis employed with a dyestuflt' which is insoluble pr but.

partially soluble in acid.

Dye soluble in water but insoluble in acid-From one one-hundredth to ten ounces of Erie fast scarlet (color index No. 326) or some similar dye, depending on the shade desired, is ground up with a small amount of sulphuric acid from the parchmentizing bath, until a fine suspension of the dye in the acid is obtained. This is added to the parchmentizing bath'so that the above amount is contained in one pound of parchmentizing acid. The aper is run through in the usual manner and washed in the usual way. As the water washes the acid out of the paper, the dye dissolves in it and thereb colors the amyloid which is formed at t e same time. 1

I amthus enabled to produce for the first time parchmentized paper containing various dyestufis which it has hitherto been impossible to use in the manufacture of such papers, namely, dyes which are not watersoluble. And, by this new method I am not only enabled to produce colored parchmentized papers in a greater variety of colors and shades, with less otherwise unavoid able loss of dyestuffs, and with more satisfactorily constant and controllable eifects, owing to the greater latitude in the choice of classes of dyes which may be employed in the manufacture of colored paper parchmentized by the methods described, but I am also enabled thereby to produce colors not hitherto attainable with the hitherto known and applied methods.

In the first place, the old method of applying the dyestutf in the beaters required that the coloring matter used be water-soluble. In addition to the disadvantage in the loss of coloring material b such process, this prescribed a limitation 1n the choice of dyestuffs, necessaril limiting the variety of colors and shades. Iurthermore, beyond the required quality of water-solubility, dyestuffs applied in the beaters must also be basic dyes in order that they would color the fiber of the paperas it has not been considered competent to use any mordant in a paper which was to undergo the parchmentizing treatment in the acid bath. Makers of such paper 'were therefore limited substantially to water-soluble basic dyes for the purpose of dyeing of the paper by the process of coloring in the beaters. The process of coloring the paper after its formation and before parchmentizing by impressing or imprinting the dyestufl upon the paper by rollers carr ing such colors is also limited to water-solu 1e dyes.

By being able to appl more varieties and classes of d es which have found can be used direct y in the acid parchmentizing 4 bath, I develop not only a superior product, but am enabled to make new rades of such paper incorporating dyes o a character which have never been used for the purpose. All of the limited numbers of dyes hitherto employed can also be used in my process, while with all the additional dyestufis which I am enabled to use I can produce colored parchmentized papers of colors and shades heretofore not known in the art. It will also be evident, from the foregoing explanations and examples, that appropriate mixtures and combinations of colors may be made to produce numerous tints and shades in parchmentized paper hitherto entirely unknown in this art. 7

One of the advantages of my method of coloring these papers is that it permits closely coordinated control. After experiment has once determined just. what mixtures and proportions are to be employed in order to produce any special color, shade, or tint, it is a relatively simple matter to so control the acid bath that it will be at all times of'substantially the same composition, and the finished paper can be produced always in close approximation of the selected standard of color or tint.

Sulphuric or other acids or materials have been used in archmentizing baths, but the former is pre erably employed because of its greater availability and relative cheapness. I have therefore described my process of incorporating the colors in the parchmentizing bath as set forth in the specific illustrative examples in terms relating more specifically to the use of sulphuric acid; but itwill be obvious to the paper-colorist chemist that by proper adjustment of the conditions to variations in solubilities and reactions substantially the same general treatments with necessary modifications can easily be determined by simple experiment and applied in substantially the same manner as herein set forth.

It is also obvious from the description of the process herein set forth that it is possible to make considerable variation in quantity and qualities of the dyes used according to the colors, shades, or general effects which it is desired to produce, without departing from the nature and scope of my invention, and I wish to have it understood that the examples given in this specification have been embodied for the purpose of illustration, and not by way of limitation.

What I claim as new, and for which I pray the issuance of Letters Patent, is:

1. A parchmentized paper incorporating organic acid dyes and which are not soluble in acid but soluble in water.

2. A parchmentized paper incorporating dyestufl' not soluble in acid but soluble in water.

3. A parchmentized paper incorporating dyestufi not soluble in sulphuric acid but soluble in water.

4. In the art of manufacturing colored or tinted parchmentized paper theprocess of passing the formed paper through an acid bath in which dyestuif is suspended, and subsequently passing the paper so treated through a water bath to dissolve and diffuse the dyestuif deposited in the amyloid film formed upon the fibre of the paper while passing through the acid bath, to color the paper, and to wash out any excess of acid still present.

5. In the art of manufacturing .parchmentized paper of the character described, a step in the process, comprising the treatment of the paper with an acid bath in which dyestufi is suspended.

6. In the art of manufacturin parchmentized paper of the character escribed, a step in the process, comprisin the treatment of the paper with a pare mentizing bath in which dyestuif is suspended.

7. In the art of manufacturing arch- 'mentized paper of the character described, a

step in the process, comprisingthe treatment of the paper with a sulphuric acid bath, in which dyestufi' is suspended.

8. 'I'intedarchmentized pa er which has the dyestu i incorporated su stantially in the amyloid coating formed upon the fibre of the paper by the parchmentizing bath.

9. In the rocess of parchmentizing paper, the ad ition of dyestufi to a parchmentizing bath, the said dye being insoluble in said bath.

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10. In the process of archmentizing paper, the addition of acid insoluble dyestufi' to an acid parchinentizing bath.

11. In the process of manufacturing parchmentized pa er which embraces" a step consisting in treating such pa er in an acid bath, the addition of an acid insoluble dyestuff to said acid bath.

12. In the recess of manufacturing colored or tinted parchmentized paper, which embraces a step consisting) in treating such paper in a sulphuric acid ath, the addition of a dyestufi insoluble in said acid hath.

13. A parchment-ized paper incorporatin organic direct dye not soluble in acld but so uble in Water.

It. in the art of manufacturing colored or tinted parchmentized paper, the process of passing the formed paper through a A parchmentizing bath in which dyestufi is at least in 'part suspended, then passing the paper through a Water bath to dissolve and difiuse the dyestufi, which has been deposited in the amyloid film formed upon the fibre of the pap-er While passing through the parchmentizmg bath, and to ash out the excess of parchmentizing agent still present after the formation of the amyloid film upon the surfaces of the aper.

- ROPBERT IR ING COWIEN.

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